The mainstream research into Cameras-on-CMOS (CoC) technology has been focused on front-illuminated architectures, in which the Pixel Sensor and the signal processing circuitry are integrated in the same plane. This architecture is disadvantaged in a number ways, including the incompatibility of different CCD and CMOS processing technologies that are currently used and low Fill Factors.
Camera-on-a-CMOS chip will be an inevitable component of future intelligent vision systems. However, up till now, the dominant format of data in imaging devices is still analog. The analog photocurrent or sampled voltage is transferred to the ADC via a column or a column/row bus. Moreover, in the active pixel configuration the area occupied by circuitry reduces significantly the fill factor, so that there are heavy constraints imposed on the size of the circuits used.
This invention provides a novel approach towards rapid image capture and image matching based on a combination of image sensor and Memristor-based storage/compare cell implemented as part of meta-security cameras and similar systems that can perform multiplicity of tasks such as image matching, image tracking and motion detection at low power. Additionally, an approach for image tracking and motion detection is disclosed.
In our structure, both image capture and image matching is carried out at the same time. Significant advantage of this invention is its high-speed capability as well as providing a very secure imaging environment when power source is disrupted or completely removed. The imager is able to retain its previous state when power source is reinstated allowing complete recovery of image data.
The existence of Memristor (M) was conceptually predicted by Chua in 1971 and generalized by Kang in 1976. Chua postulated that a new circuit element defined by the single-valued relationship dφ=Mdq must exist whereby current moving through the memristor M is proportional to the flux φ of the magnetic field that flows through the material. In another words, the magnetic flux φ between the terminals is a function of the amount of charge, q that has passed through the device. This follows from Lenz's law whereby the single-valued relationship dφ=Mdq has the equivalence v=M(q)i, where v and i are memristor voltage and current, respectively. In one form the memristor behaves as a switch, much similar to a transistor. However, unlike the transistor, it is a 2-terminal rather than a 3-terminal device and does not require power to retain either of its two states. A memristor changes its resistance state between two upper and lower bound values and can have multiplicity of values between these two limits. This is achieved via the movement of mobile ionic charge within an oxide layer.
Furthermore, these resistive states are non-volatile. This behavior is an important property in forensic investigation as an example that influences the architecture of image sensor systems and meta-security cameras, where the power supply of imager and stored image template blocks can be disabled without loss of stored image data.